Antibiotics in patients with severe burn injury-A modifiable variable in hypernatremia etiology

INTRODUCTION

Hypernatremia is a common problem among patients with severe burn injuries and seems to be associated with an unfavorable clinical outcome. The current study was designed to evaluate the impact of antibiotics with a high proportion of sodium on this phenomenon.

METHODS

All admissions to our burn center from 01/2017 till 06/2023 were retrospectively screened. All patients aged >18 years which suffered from at least 20 % total body surface burned area (TBSA) 2nd degree burn injuries or more than 10 % TBSA when including areas of 3rd degree burn injuries were included. The course of the serum Na-level was analyzed from two days before till two days after the start of the antibiotic treatment. Ampicillin/sulbactam, cefazoline and piperacillin/tazobactam were classified as high-dose sodium antibiotics (HPS), meropenem and vancomycin as low-dose sodium antibiotics (LPS).

RESULTS

120 patients met the inclusion criteria. A significant increase of the serum Na was detectable in the HPS group on day 1 and 2 after initiating the antibiotic treatment (n = 64, day 1: 2,1 (SD 4,18) mmol/l, p < 0,001; day 2: 2,44 (SD 5,26) mmol/l, p < 0,001) while no significant changes were detectable in the LPS group (n = 21, day 1: 0,18 (SD 7,45) mmol/l, p = 0,91; day 2: -0,27 (SD 7,44) mmol/l, p = 0,87). This effect was further aggravated when analyzing only the HPS patients with a TBSA ≥30 % (n = 33; day 1: 2,93 (SD 4,68) mmol/l, p = 0,002; day 2: 3,41 (SD 5,9) mmol/l, p = 0,003).

CONCLUSION

The amount of sodium in antibiotics seems to have a relevant impact on the serum Na during the early stages of severe burn injury. Therefore, this aspect should be taken into account when searching for the most appropriate antibiotic treatment for patients with severe burn injury, especially when being at acute risk for a clinical relevant hypernatremia.

Severe Burn Injuries - The Day the Sodium Starts Rising

BACKGROUND/AIM

The current study was designed to evaluate the etiologies of hypernatremic episodes in patients with severe burn injuries in comparison to critically ill non-burn patients.

PATIENTS AND METHODS

The retrospective data acquisition was limited to the first 14 days and to patients with at least 20% total body surface area (TBSA) 2nd degree burn injuries or more than 10% TBSA when including areas of 3rd degree burn injuries. The results were compared to the results of a previously published study that analyzed the risk factors for hypernatremia in 390 non-burn intensive care unit patients.

RESULTS

In total, 120 patients with a total of 50 hypernatremic episodes were included. Compared to non-burn injury patients, no significant differences were detectable except for a lower rate of hypokalemia and a higher rate of mechanical ventilation. The main trigger for hypernatremic episodes was the loss of free water, while 24% of the hypernatremic episodes seemed to be at least partly triggered by a surplus sodium influx. Patients with hypernatremic episodes had a significantly higher mortality rate. However, in none of the cases was hypernatremia the decisive cause of death.

CONCLUSION

Besides the unique phenomenon of high volume internal and external volume shifts, the overall risk factors and etiologies of hypernatremia in patients with severe burn injury do not seem to significantly differ from other ICU patient collectives. Remarkably, a surplus of sodium influx and therefore a modifiable factor besides the specific burn injury volume resuscitation had an impact on the hypernatremic episodes in 24% of cases.

Outpatient care for facial palsy-a survey on patient satisfaction in uni- and interdisciplinary approaches

Objective

The various causes of facial palsy, diagnostic methods and treatment approaches frequently involve different medical specialities. Nevertheless, there exist only few specialized consultation and therapy services for patients with facial palsy (FP) in Germany. The aim of the present study was to evaluate factors affecting quality of life (QoL) and treatment satisfaction of patients presenting to an interdisciplinary facial nerve outpatient clinic.

Methods

The study analyzed patients presenting to the interdisciplinary facial palsy outpatient clinic in Tuebingen between February 2019 and December 2022. General satisfaction and QoL was estimated by numerous self-rating questionnaires: ZUF-8, SF-36, FDI, FaCE, PHQ-9. An ANOVA was performed to analyze determinants affecting the ZUF-8. Correlation analyses between cause and regeneration of FP as well as questionnaire scores were performed. Results were compared with a group of patients who were managed in an unidisciplinary setting.

Results

In total, 66 patients with FP were enrolled. FP patients showed increased levels of depression (PHQ-9: 14.52 ± 3.8) correlating with recovery of the palsy (p = 0.008), FaCE (p < 0.001) and FDI ratings (p < 0.001). There was a high level of satisfaction with the services provided during the uni-and interdisciplinary consultation (ZUF-8: 24.59 ± 6.2), especially among the 12/66 patients who received reconstructive, surgical treatment. However, some patients requested more psychological and ophthalmological support.

Conclusion

High levels of treatment satisfaction can be achieved in both an uni-and interdisciplinary setting. However, multimodal therapy approaches should be applied, considering physical and psychological aspects. In the absence of recovery, surgical interventions must be considered as treatment options. Further studies should continue to investigate potential differences between uni-and interdisciplinary treatment.

[Secondary surgical procedures following motor nerve injuries]

BACKGROUND

The functional deficits that develop after a peripheral nerve injury mean a considerable reduction in the quality of life for the affected patients. However, interventions on the injured nerve are not always possible or effective. In this case, secondary procedures, e.g. tendon transfers, are a feasible option for functional reconstruction.

OBJECTIVES

An overview of the most common secondary surgical procedures for functional reconstruction after peripheral nerve injuries.

METHODS

Presentation and discussion of the most common secondary surgical procedures with emphasis on tendon transfers. Illustration of the primary functions that need to be reconstructed depending on the respective nerve lesion.

RESULTS

The basic principle of secondary surgical procedures after nerve injuries is the transposition of a healthy tendomuscular unit to replace a lost function following a loss of muscle or tendon or if an intervention on the nerve is not promising. For example, by transferring flexor forearm muscles, wrist, finger and thumb extension can be reconstructed after radial nerve injury. By transposing the tibialis posterior muscle, dorsiflexion in the talocrural joint can be restored to enable the affected patient to walk safely without an orthosis.

CONCLUSIONS

Secondary surgical procedures are a valuable option for functional reconstruction after nerve injury.

Influence of colored face masks on judgments of facial attractiveness and gaze patterns

BACKGROUND

Facial aesthetics are of great importance in social interaction. With the widespread adoption of face masks in response to the Covid-19 pandemic, there is growing interest in understanding how wearing masks might impact perceptions of attractiveness, as they partially or completely conceal facial features that are typically associated with attractiveness.

OBJECTIVES

This study aimed to explore the impact of mask wearing on attractiveness and to investigate whether the color (red or blue) of the mask has any effect on the perception of a person's attractiveness, while also considering gender and age as contributing factors. Additionally, the study intended to evaluate gaze patterns, initial focus, and dwell time in response to masked and unmasked faces.

METHODS

30 AI-generated images of 15 female and 15 male faces were presented to 71 participants (35 male, 36 female) in 3 conditions: not wearing any mask, wearing a red surgical mask, and wearing a blue surgical mask. The perceived attractiveness was rated on an ordinal scale of 1-10 (10 being most attractive). Gaze behavior, dwell time and initial focus were recorded using a stationary eye-tracking system.

RESULTS

The study found that wearing masks had no significant effect on the attractiveness ratings of female faces (p = .084), but it did benefit the perceived attractiveness of male faces which were initially rated lower (p = .16). Gender and age also played a significant role, as both male and female participants rated female stimuli higher than male stimuli (p < .001), and younger participants rated both genders as less attractive than older participants (p < .01). However, there was no significant influence of the mask's color on attractiveness. During the eye-tracking analysis, the periorbital region was of greater interest while masked, with the time to first fixation for the eyes being lower than the non-masked stimulus (p < .001) and showed a longer dwell time (p < .001). The lower face was shown less interest while masked as the time to first fixation was higher (p < .001) and the fixation count was less (p < .001). Mask color did not influence the scan path and there was no difference in revisits to the mask area between red or blue masks (p = .202), nor was there a difference in time to first fixation (p = .660).

CONCLUSIONS

The study findings indicate that there is an interplay between the gender and age of the participant and the facial stimuli. The color red did have an effect on the perception attractiveness, however not in female faces. The results suggest that masks, especially red ones, might be more beneficial for male faces, which were perceived as less attractive without a mask. However, wearing a mask did not significantly impact already attractive faces. The eye-tracking results revealed that the periorbital region attracted more attention and was fixated on more quickly while wearing a mask, indicating the importance of eyes in social interaction and aesthetic perception.

Insomnia-A Systematic Review and Comparison of Medical Resident's Average Off-Call Sleep Times

Sleep deprivation is known to have serious consequences, including a decrease in performance, attention and neurocognitive function. It seems common knowledge that medical residents are routinely sleep deprived, yet there is little objective research recording their average sleep times. To discern whether residents may be suffering from the abovementioned side effects, this review aimed to analyze their average sleep times. Thirty papers recording the average sleep time of medical residents were found via a literature search using the key words "resident" and "sleep". An analysis of the mean sleep times cited therein revealed a range of sleep from 4.2 to 8.6 h per night, the median being 6.2 h. A sub-analysis of papers from the USA showed barely any significant differences in sleep time between the specialties, but the mean sleep times were below 7 h. The only significant difference (p = 0.039) was between the mean sleep times of pediatric and urology residents, with the former achieving less sleep. The comparison of methods for data collection showed no significant difference in the sleep times collected. The results of this analysis imply that residents are regularly sleep deprived and may therefore suffer from the abovementioned consequences.

Outcome of Surgery as Part of Palliative Care of Patients with Symptomatic Advanced or Metastatic Extra-Abdominal High-Grade Soft Tissue Sarcoma

Background

The modern multimodal treatment of malignant tumors has increased disease-specific survival and decreased the burden of tumor-associated complications. The main focus of palliative surgery is not based primarily on quantitative success parameters of tumor response but is instead mainly on the question of quality of life.

Aim

The current study was conducted to analyze the clinical and oncological outcomes of palliative patients with soft tissue sarcoma.

Design

Of 309 patients with extra-abdominal high-grade soft tissue sarcoma treated between August 2012 and December 2014, our retrospective analysis revealed 33 palliative patients for this study. All patients were evaluated and managed by a multidisciplinary team with expertise and experience in sarcoma treatment. The survival analysis was made using the Kaplan-Meier method.

Results

The main sarcoma symptoms were pain (27.3%) and ulcerated tumors or shortly before ulceration (24.2%). Thirteen patients (39.4%) were operated on with negative margins, 15 (45.5%) with positive margins, 2 with tumor debulking (6.1%), and 3 patients (9.1%) were treated only with palliative hyperthermic isolated limb perfusion. Ten pedicle flaps were performed after sarcoma resection. The median operation time was 85 minutes (range, 37-216 minutes). The median hospitalization stay was 9.5 days (range, 3-27 days). No patients died during hospitalization. Twelve-month disease-free survival was 48.5% (95% confidence interval: 45.4-51.6).

Conclusions

Palliative surgery of metastatic or advanced soft tissue sarcoma can improve the wound care and quality of life. Closed noninfected wounds enable further treatment options, such as chemotherapy, immunotherapy, and radiotherapy. This surgery should be considered during the discussion on interdisciplinary tumor boards.

Precision of Dynamic Infrared Thermography in Anterolateral Thigh Flap Planning: Identification of the Perforator Fascia Passage

Background The anterolateral thigh (ALT) flap is commonly utilized in reconstructive surgery. Preoperative perforator mapping facilitates dissection. Dynamic infrared thermography can be applied to identify ALT perforators. However, its accuracy has not been evaluated in detail before. Therefore, this study aimed to assess the precision of dynamic infrared thermography in ALT perforator localization.

Methods The survey site was defined as a 25 × 8 cm rectangle on the anterolateral thigh and a coordinate system was established. The area was examined consecutively by dynamic infrared thermography with a FLIR ONE camera after 2-minute fan precooling. Two surgeons then independently performed color duplex ultrasound on the basis of the identified hotpots.

Results Twenty-four healthy subjects were examined. About 74.8% of perforators were musculocutaneous or musculoseptocutaneous. The mean distance between study area center and perforator or hotspot center was 51.8 ± 27.3 and 46.5 ± 26.2 mm, respectively. The mean distance from hotspot center to sonographic perforator fascia passage was 15.9 ± 9.9 mm with a maximum of 48.4 mm. The positive predictive value of thermographic ALT perforator identification was 93%.

Conclusion Thermographic hotspot and perforator location diverge widely in ALT flaps. Dynamic infrared thermography can therefore not be used as standalone technique for preoperative ALT perforator identification. However, the application before color duplex ultrasound examination is a reasonable upgrade and can visualize angiosomes and facilitate the examination.

Soft tissue reconstruction of complex infra-inguinal wounds following revisionary vascular surgery

INTRODUCTION

Large, full thickness infra-inguinal wounds following revision revascularization procedures of the lower extremity are a challenging complication for reconstructive surgery. Frequently, these patients present with various comorbidities and after several previous reconstructive attempts and therefore no straightforward soft tissue reconstruction is likely.

METHODS

Patients who presented with large, complex inguinal wounds for soft tissue reconstruction were analyzed retrospectively in terms of flap choice, outcome and complication rates. A focus was set on the reconstructive technique and a subgroup analysis was assessed.

RESULTS

19 patients (11 men, 8 women) who received 19 flaps (17 pedicled, two free flaps) were included in this retrospective study. Average patient age was 73.3 years (range: 53-88 years). 10 fascio-cutaneous flaps (ALT, 52.6%) and 9 muscle flaps (47.4%) were applied. Among muscle flaps, 3 pedicled gracilis flaps, 4 pedicled rectus abdominis flaps and two free latissimus dorsi flaps were used. No flap losses were observed except one case of limited distal flap necrosis (gracilis group). Body Mass Index (BMI) ranged from 19 to 37, mean 26.8. Mean surgery time in all patients was 165.9 minutes (range: 105-373 minutes). Revision surgery due to local wound healing problems averaged 1.6 in all patients. In all cases sufficient soft tissue reconstruction was achieved and bypasses were preserved. Lengths of stay averaged 27.2 (14 to 59 days). Mortality was considerably (10.5%) due to systemic complications (One patient died due to a heart attack 4 weeks postoperatively, another patient died due to an extensive pulmonary embolism two weeks postoperatively).

CONCLUSION

Soft tissue reconstruction of complex inguinal wounds after revision vascular surgery is challenging and wound-healing problems are expectable. In addition to the rectus abdominis flap the pedicled ALT flap is feasible in a broad variety of medium to large wounds. Free flap reconstruction is recommended for very large defects. A structured interdisciplinary approach is required for the management of complex wounds after vascular surgery to prevent and to deal with complications and perioperative morbidity.

The Grasping Test Revisited: A Systematic Review of Functional Recovery in Rat Models of Median Nerve Injury

The rat median nerve model is a well-established and frequently used model for peripheral nerve injury and repair. The grasping test is the gold-standard to evaluate functional recovery in this model. However, no comprehensive review exists to summarize the course of functional recovery in regard to the lesion type. According to PRISMA-guidelines, research was performed, including the databases PubMed and Web of Science. Groups were: (1) crush injury, (2) transection with end-to-end or with (3) end-to-side coaptation and (4) isogenic or acellular allogenic grafting. Total and respective number, as well as rat strain, type of nerve defect, length of isogenic or acellular allogenic allografts, time at first signs of motor recovery (FSR) and maximal recovery grasping strength (MRGS), were evaluated. In total, 47 articles met the inclusion criteria. Group I showed earliest signs of motor recovery. Slow recovery was observable in group III and in graft length above 25 mm. Isografts recovered faster compared to other grafts. The onset and course of recovery is heavily dependent from the type of nerve injury. The grasping test should be used complementary in addition to other volitional and non-volitional tests. Repetitive examinations should be planned carefully to optimize assessment of valid and reliable data.

Beyond the Knife-Reviewing the Interplay of Psychosocial Factors and Peripheral Nerve Lesions

Peripheral nerve injuries are a common clinical problem. They not only affect the physical capabilities of the injured person due to loss of motor or sensory function but also have a significant impact on psychosocial aspects of life. The aim of this work is to review the interplay of psychosocial factors and peripheral nerve lesions. By reviewing the published literature, we identified several factors to be heavily influenced by peripheral nerve lesions. In addition to psychological factors like pain, depression, catastrophizing and stress, social factors like employment status and worker's compensation status could be identified to be influenced by peripheral nerve lesions as well as serving as predictors of functional outcome themselves, respectively. This work sheds a light not only on the impact of peripheral nerve lesions on psychosocial aspects of life, but also on the prognostic values of these factors of functional outcome. Interdisciplinary, individualized treatment of patients is required to identify patient at risk for adverse outcomes and provide them with emotional support when adapting to their new life situation.

[The proximally pedicled anterolateral thigh flap for reconstruction of complex soft tissue wounds of the hip and caudal trunk region]

INTRODUCTION

Groin and lower trunk defects are common problems, especially for elderly patients. While groin defects are often due to prior vascular interventions, trochanteric defects are mainly caused by pressure sores. Plastic reconstructive methods are manifold; however, the pedicled anterolateral thigh (ALT) flap is supposed to be reliable with sustainable results.

OBJECTIVE

We present our experiences using the pedicled ALT flap for soft tissue reconstruction in patients with large wounds of the medial and lateral proximal thigh.

MATERIALS AND METHODS

A total of 16 patients with groin and lower trunk defects due to prior vascular surgery or pressure sores received locoregional soft tissue reconstruction using a proximal pedicled ALT flap. Patient characteristics, defect size, surgery time, clinical outcome and complication rate were assessed.

RESULTS

With the exception of two cases, sufficient soft tissue reconstruction was achieved. In all, 81,3% of patients were categorized as ASA (American Society of Anesthesiologists) 3. The average duration of surgery was 149 min. Length of stay was 18,3 days. A total of 31% needed revision surgery due to limited wound healing problems. Two patients died. All patients showed healed wound conditions when they were discharged.

CONCLUSION

The proximal pedicled ALT-flap is a reliable method for soft tissue reconstruction in groin and lower trunk defects. This reconstructive procedure enables reliable wound closure, especially in elderly patients with substantially reduced general health condition.

Evaluation of angiogenesis, epithelialisation and microcirculation after application of polyhexanide, chitosan and sodium chloride in rodents

The purpose of this study was to investigate the effect of polyhexanide and a new developed chitin-based wound dressing on skin microcirculation, epithelialisation and angiogenesis. A full-thickness dermal layer extending to the underlying cartilage was excised on the dorsal side of hairless mice (n = 27; 2·3 ± 0·3 mm² ). A polyhexanide ointment, a chitosan solution and a sodium chloride group as control were analysed using intravital fluorescence microscopy. Angiogenesis, epithelialisation and microcirculatory standard parameters were measured over a time period of 20 days. The non-perfused area is regarded as a parameter for angiogenesis and showed the following results: on days 12, 16 and 20, the sodium chloride group was significantly superior to chitosan solution (P < 0·05) and, on days 8, 12, 16 and 20, the polyhexanide group was superior to chitosan solution (P < 0·05). The epithelialisation was measured significantly faster in the polyhexanide and control group on day 8 versus chitosan solution. Whereas polyhexanide and sodium chloride were nearly completely epithelialised, treatment with chitosan solution showed still an open wound of 11% of the initial wound size. Altogether, we could demonstrate the advantageous effects of a polyhexanide ointment on microcirculation, angiogenesis and epithelialisation. Chitosan solution appears to inhibit angiogenesis and delays epithelialisation. Further studies in different models would be worthwhile to confirm these results.

Influence of ISDN, L-NAME and selenium on microcirculation, leukocyte endothelium interaction and angiogenesis after frostbite

BACKGROUND

The body of knowledge regarding the different facets of frostbite injury continues to expand. However, beside the administration of physiological saline, local rewarming, local disinfection and symptomatic medications, today no causal therapy is known which would accelerate angiogenesis and wound healing. The aim of this study was to investigate the influences of dilative acting drugs on microcirculation, angiogenesis and leukocyte behavior.

MATERIALS AND METHODS

Ears of male hairless mice (n=40) were inflicted with full thickness frostbites using a cold air jet. Then the affects of four intraperitoneal injections of isosorbitdinitrate (ISDN, n=10), l-nitroarginine-methyl-ester (l-NAME, n=10), selenium (n=10) or sodium chloride (n=10; each administered to one of four corresponding study groups), on microcirculation, leukocyte-endothelial interaction and angiogenesis were investigated over a 12-day period using intravital fluorescent microscopy.

RESULTS

Angiogenesis was most improved by ISDN (36.8 vs. 54.5% non-perfused area on day 3, 3.9 vs. 17.0% on day 7 compared to selenium, p<0.006). Venular diameter was most significantly dilated in the ISDN-group, l-NAME showed significantly decreased diameter over the complete time of 12 days. ISDN had positive influences on edema formation, which was significantly reduced compared to control (27% lower values compared to control; p=0.007 on day 3). The l-NAME-group showed the significant highest leukocyte-adhesion compared to control on days 7 and 12 (53% resp. 58% higher, p<0.006).

CONCLUSION

Overall, out of all the drugs tested, ISDN improved angiogenesis, dilated venules and decreased edema formation and therefore seems to have the greatest positive impact on these crucial parameters after frostbite injury.

Repetitive extracorporeal shock wave applications are superior in inducing angiogenesis after full thickness burn compared to single application

OBJECTIVE

Burn wounds remain a challenge due to subsequent wound infection and septicemia, which can be prevented by acceleration of wound healing. The aim of the study was to analyze microcirculation and leukocyte endothelium interaction with particular focus on angiogenesis after full-thickness burn using three different repetitions of low energy shock waves.

METHODS

Full-thickness burns were inflicted to the ears of hairless mice (n=44; area: 1.6±0.05 mm2 (mean±SEM)). Mice were randomized into four groups: the control group received a burn injury but no shock waves; group A received ESWA (0.03 mJ/mm2) on day one after burn injury; group B received shock waves on day one and day three after burn injury; group C ESWA on day one, three and seven after burn injury. Intravital fluorescent microscopy was used to assess microcirculatory parameters, angiogenesis and leukocyte interaction. Values were obtained before burn (baseline value) immediately after and on days 1, 3, 7 and 12 after burn.

RESULTS

Shock-wave treated groups showed significantly accelerated angiogenesis compared to the control group. The non-perfused area (NPA) is regarded as a parameter for angiogenesis and showed the following data on day 12 2.7±0.4% (group A, p=0.001), 1.4±0.5% (group B, p<0.001), 1.0±0.3% (group C, p<0.001), 6.1±0.9% (control group). Edema formation is positively correlated with the number of shock wave applications: day 12: group A: 173.2±9.8%, group B: 184.2±6.6%, group C: 201.1±6.9%, p=0.009 vs. control: 162.3±8.7% (all data: mean±SEM).

CONCLUSION

According to our data shock waves positively impact the wound healing process following burn injury. Angiogenesis showed significantly improved activity after shock wave application. In all three treatment groups angiogenesis was higher compared to the control group. Within the ESWA groups, double applications showed better results than single application and three applications showed better results than single or double applications.

Extracorporeal shock waves improve angiogenesis after full thickness burn

OBJECTIVE

Extensive wounds of burn patients remain a challenge due to wound infection and subsequent septicemia. We wondered whether extracorporeal shock wave application (ESWA) accelerates the healing process. The aim of the study was to analyze microcirculation, angiogenesis and leukocyte endothelium interaction after burns by using ESWA with two types of low intensity.

METHODS

Full-thickness burns were inflicted to the ears of hairless mice (n=51; area: 1.3 mm(2)). The mice were randomized into five groups: (A) low-energy shock waves after burn injury (0.04 mJ/mm(2)); (B) very low-energy shock waves after burn injury (0.015 mJ/mm(2)); (C) mice received burns but no ESWA (control group); (D) mice without burn were exposed to low-energy shock waves; (E) mice without burns and with no shock wave application. Intravital fluorescent microscopy was used to assess microcirculatory parameters, angiogenesis and leukocyte behavior. ESWA was performed on day 1, 3 and 7 (500 shoots, 1 Hz). Values were obtained straight after and on days 1, 3, 7 and 12 post burn.

RESULTS

Group A showed accelerated angiogenesis (non-perfused area at day 12: 5.3% vs. 9.1% (group B) and 12.6% (group C), p=0.005). Both shock wave groups showed improved blood flow after burn compared to group C. Shock waves significantly increased the number of rolling leukocytes compared to the non-ESWA-treated animals (group D: 210.8% vs. group E: 83.3%, p=0.017 on day 7 and 172.3 vs. 90.9%, p=0.01 on day 12).

CONCLUSION

Shock waves have a positive effect on several parameters of wound healing after burns, especially with regard to angiogenesis and leukocyte behaviour. In both ESWA groups, angiogenesis and blood flow outmatched the control group. Within the ESWA groups the higher intensity (0.04 mJ/mm(2)) showed better results than the lower intensity group. Moreover, shock waves increased the number of rolling and sticking leukocytes as a part of an improved metabolism.

Guidelines for palliative surgery of cholangiocarcinoma

The aims of the guidelines are to help assess the evidence for palliation surgery in patients with cholangiocarcinoma (CCA). The guidelines are classified in accordance with the location of the primary lesion, i.e. intrahepatic, hilar, and distal. They are based on comprehensive literature surveys, including results from randomized controlled trials, systematic reviews and meta-analysis, and cohort, prospective, and retrospective studies. Intrahepatic CCA, i.e. resection of lymph-node-positive tumors and R1/R2 resections have not been shown to provide survival benefit: Evidence levels: 2b, 4; Recommendation grade C. Hilar CCA: R1 resection is justified as a very efficient palliation. Non-surgical biliary stenting is the first choice of palliative biliary drainage. Distal CCA: Resection of lymph-node-positive tumours and R1/R2 resections should be performed. Non-surgical stenting is regarded as the first choice of palliation for patients with short life expectancy. For patients with longer projected survival, surgical bypass should be considered. Palliative resections have a relevant beneficial impact on the outcome of patients with distal and hilar CCA. Non-surgical stenting is the first choice of palliative biliary drainage for patients with hilar CCA and for those with distal CCA and short life expectancy. For patients with distal CCA and longer projected survival, surgical bypass should be considered.

Sirolimus improves early microcirculation, but impairs regeneration after pancreatic ischemia-reperfusion injury

Ischemia and reperfusion injury remains a relevant problem in clinical pancreas transplantation. We investigated the effect of sirolimus (SRL) in a rodent model of 90-min warm pancreatic ischemia. Four groups were studied: (1) sham surgery and vehicle; (2) sham surgery and SRL; (3) warm ischemia and vehicle; (4) warm ischemia and SRL. SRL (1.5 mg/kg/day) and vehicle were administered intraperitoneally for 3 days prior to surgery until the animals were killed. Microcirculation was assessed immediately after reperfusion by means of intravital fluorescence microscopy. Histopathological injury, apoptosis, proliferation and biochemical parameters were analyzed at 2 h, 1 day and 5 days after surgery. Ninety minutes after ischemia, intravital microscopy revealed an improved functional capillary density (p < 0.05) and reduction of adherent leucocytes (p < 0.01) and platelets (p < 0.05) in the SRL-treated group compared to the vehicle-treated controls. In contrast, on day 5 after ischemia, the pancreatic tissue of SRL-treated animals showed a higher grade of histological injury (p < 0.05) and higher rate of apoptotic cells (p < 0.05) than the vehicle controls. In summary, our data indicate that administration of SRL improves microcirculation at a very early stage, but results in an impairment of the recovery phase after pancreatic ischemia-reperfusion injury.

Fusion of small unilamellar vesicles onto laterally mixed self-assembled monolayers of thiolipopeptides

Monolayers of the thiolipopeptide NH(2)-Cys-Ala-Ser-Ala-Ala-Ser-Ser-Ala-Pro-Ser-Ser-(Myr)Lys(Myr)-OH (III) were formed on gold surfaces by self-assembly, mixed with a lateral spacer of the same peptide composition, NH(2)-Cys-Ala-Ser-Ala-Ala-Ser-Ser-Ala-Pro-Ser-Ser-Lys-OH (I). Different mixing ratios were employed ranging from 0.1 to 1, corresponding to 10-100% thiolipopeptide. These self-assembled monolayers (SAMs) were then exposed to a suspension of liposomes with the aim of forming lipid bilayers as a function of the mixing ratio. A clear optimum with respect to homogeneity and electrical properties of the membranes was obtained in the middle region (0.5) of mixing ratio, as revealed by surface plasmon resonance spectroscopy, impedance spectroscopy, and fluorescence microscopy. The combination of these methods was shown to be a powerful tool, although a true lipid bilayer was not obtained. Instead, vesicle adsorption was shown to be the predominant process, and FRAP (fluorescence recovery after photobleaching) measurements showed that the films were not fluid on the micrometer length scale.

Volumetric object modeling for surgical simulation

Surgical simulation has many applications in medical education, surgical training, surgical planning and intra-operative assistance. However, extending current surface-based computer graphics methods to model phenomena such as the deformation, cutting, tearing or repairing of soft tissues poses significant challenges for real-time interactions. This paper discusses the use of volumetric methods for modeling complex anatomy and tissue interactions. New techniques are introduced that use volumetric methods for modeling soft-tissue deformation and tissue cutting at interactive rates. An initial prototype for simulating arthroscopic knee surgery is described which uses volumetric models of the knee derived from 3-D magnetic resonance imaging, visual feedback via real-time volume and polygon rendering, and haptic feedback provided by a force-feedback device.

Naturally occurring conjugated bile acids, measured by high-performance liquid chromatography, in human, dog, and rabbit bile

The aim of this study was to determine the biliary pattern of conjugated bile acids after stimulation of their enterohepatic circulation. Conjugated bile acids were separated by reversed-phase ion-pair chromatography without prior derivatization. A MicroPak SP-C18-IP-4 column was used as non-polar matrix, and an ionic alkyl compound, tetrabutylammonium phosphate, was added to the mobile phase, which was a mixture of acetonitrile and water. Quantification was made by UV absorption at 210 nm with external standardization. In fourteen human patients with external biliary drainage after papillotomy there was preferential glycine conjugation. The mean values were 36.5% for glycocholic acid, 33% for glycochenodeoxycholic acid, and 10.0% for glycodeoxycholic acid. Only 15.2% of the biliary bile acids were taurine metabolites. Conjugates of ursodeoxycholic acid were below 2.1%. In most cases, conjugated lithocholic acid was not detected. Within 4 h after ingestion of a standardized meal there were no significant changes in the biliary bile acid pattern. In four dogs (beagles), glycine-conjugated bile acids were lacking. The mean values were 74.3% for taurocholic acid, 14.9% for taurodeoxycholic acid, and 5.3% for taurochenodeoxycholic acid. In six rabbits, 87.4% of biliary bile acids was identified as glycodeoxycholic acid and 5.3% as glycocholic acid. In conscious dogs, as well as in rabbits, the stimulation of biliary secretion by cholecystokinin and/or secretin had no effect on the biliary bile acid spectrum. Evidently, there is a difference in the biliary composition of conjugated bile acids between humans, dogs, and rabbits. Because of the different physicochemical behaviour of glycine- and taurine-conjugated bile salts, it seems difficult to compare the therapeutic effect of gallstone dissolution in various species.

Measurement of conjugated bile acids by ion-pair high-performance liquid chromatography

Vhe quantitatively most important conjugated bile acids in man were separated by reversed-phase ion-pair chromatography without prior derivatization. As non-polar matrix an Ultrasphere I.P. column (C18) was used, and an ionic alkyl compound, tetrabutylammonium phosphate, was added to the mobile phase, which was a mixture of acetonitrile and water. Under these conditions, the glycine and taurine conjugates of cholic acid, chenodeoxycholic acid and deoxycholic acid were separated within 15 min. At 214 nm, the minimum measurable concentration was 1.3-2.0 nmol/ml. The average recovery from bile was 94%. In ten patients with biliary drainage an average of 79.5% of the bile acids were glycine conjugates.